How do people evaluate the transformation of a local music scene under tourism? Using Jacques Lacan’s mirror stage theory, Manuel Castells’ identity theory and Erik Cohen’s authentication theory, we build a framework to judge the authenticity of Naxi music in Lijiang, China, based on interviews, literature analysis and performance analysis. The conclusions are as follows. First, there are significant differences in authenticity among the three stages of Naxi music, as defined by Lacan’s theory. Second, we modify Erik Cohen’s authentication concept from the perspective of Lacan and read the spirit of persistence and innovation as “hot” authentication in the postmirror stage. Naxi musicians have clear project identity, as defined by Manuel Castells. Project identity means that they do not follow the mirror image of tourists blindly and pay attention to music and their own development. This research contributes to the sustainable development of intangible cultural heritage in tourism.